1. Field of the Invention
The present invention relates to power carrier systems for carrying articles to a desired position or positions with the aid of a power source, and more particularly to the power carrier systems of a belt-type that uses an endless belt as a carrier unit moving means.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional power carrier system of the above-mentioned belt-type will be briefly described with reference to FIG. 15 of the accompanying drawings.
FIG. 15 shows a part of the belt-type carrier system. The carrier system comprises a toothed belt 1. As shown, the belt 1 is formed with teeth on its inner surface. Although now shown in the drawing, the belt 1 extends along a given route to constitute a loop. In order to connect opposed ends 1a of the belt 1, the following end connecting structure is employed. That is, the opposed ends 1a of the belt 1 abut against each other and are put on a first toothed fixing plate 3. As shown, the teeth of the fixing plate 3 and those of the belt 1 are snugly mated with each other. A second fixing plate 2 is put on the opposed ends 1a of the belt 1. A plurality of connecting bolts 4 pass through bores formed in the second fixing plate 2, the ends of the belt 1 and the first fixing plate 3. A plurality of nuts 5 (only one is shown) are tightly engaged with projected lower ends of the bolts 4. With this, the opposed ends 1a of the belt 1 are connected and thus the belt 1 has an endless loop structure. Although not shown in the drawing, a major part of a carrier unit is installed on the second fixing plate 2. As may be understood from FIG. 10, the endless belt 1 is put around spaced pulleys, each pulley having teeth meshed with the teeth of the belt 1. One of the pulleys is a drive pulley that is driven by a power source, such as an electric motor. Thus, when the electric motor is energized, the drive pulley is turned and thus the belt 1 is moved. By changing the direction of electric current fed to the electric motor, the belt 1 and thus the carrying plate on the belt 1 is moved in one and the other directions.
However, due to its inherent construction, the above-mentioned structure for connecting opposed ends 1a of the belt 1 fails to have an adequately flexible characteristic. Thus, if the belt 1 having such opposed end connecting structure is applied to a carrier system that needs turning of the carrier unit, smoothed movement of the belt 1 is not obtained.
It is therefore an object of the present invention to provide a belt-type carrier system that is free of the above-mentioned drawback.
According to a first aspect of the present invention, there is provided a belt-type carrier system which comprises a guide rail structure having straight and curved sections, the guide rail structure having at least one track extending therealong; a belt extending along the guide rail structure; drive means for driving the belt along the guide rail structure; a spring plate put on and fixed to a part of the belt; a flexible mounting member mounted on the spring plate, the flexible mounting member being flexed when an external stress is applied thereto; a carrier base structure having at least one follower that runs on the track of the guide rail structure when the carrier base structure moves along the guide rail structure; and a universal joint structure arranged between the flexible mounting member and the carrier base structure.
According to a second aspect of the present invention, there is provided a belt-type carrier system which comprises a guide rail structure having a straight rail section, a concavely curved rail section and a convexly curved rail section, the guide rail structure having two mutually perpendicular tracks that extend therealong; a toothed belt having opposed ends that abut against each other, so that the belt constitutes a looped structure; a toothed drive pulley and a tension pulley around which the looped toothed belt is operatively put; a spring plate arranged on the opposed ends of the toothed belt; a flexible metal plate bracket including two leg portions which have lower ends mounted on the spring plate and a bridge portion which extends between upper ends of the two leg portions; a plurality of bolts and nuts by which the spring plate and the lower ends of the leg portions of the flexible metal plate bracket are connected to the opposed ends of the toothed belt; a carrier base structure having two types of followers which run on the tracks of the guide rail structure respectively when the carrier base structure moves along the guide rail structure; and a universal joint structure arranged between the bridge portion of the flexible metal bracket and the carrier base structure, the universal joint structure including a metal ball mounted on the bridge portion of the flexible metal plate bracket and a metal bush held by the carrier base structure, the metal ball being axially and pivotally movably received in the metal bracket.
According to a third aspect of the present invention, there is provided a belt-type carrier system which comprises a guide rail structure having a straight rail section, a concavely curved rail section and a convexly curved rail section, the guide rail structure having two mutually perpendicular tracks that extend therealong, a toothed belt having opposed ends that abut against each other, so that the belt constitutes a looped structure; a toothed drive pulley and a tension pulley around which the looped toothed belt is operatively put; a spring plate arranged on the opposed ends of the toothed belt; an elastic block including two leg portions which have lower ends mounted on the spring plate and a thicker bridge portion which extends between upper ends of the two leg portions; a plurality of bolts and nuts by which the spring plate and the lower ends of the leg portions of the elastic block are connected to the opposed ends of the toothed belt; a carrier base structure having two types of followers which run on the tracks of the guide rail structure respectively when the carrier base structure moves along the guide rail structure; and a universal joint structure arranged between the bridge portion of the elastic block and the carrier base structure, the universal joint structure including a cylindrical metal shaft provided on the bridge portion of the elastic block and a metal bush held by the carrier base structure, the cylindrical metal shaft being axially and rotatably received in the metal bush.